Process and device for destructive distillation



p 1954 D. DALIN ET AL PROCESS AND DEVICE FOR DESTRUCTIVE DISTILLATION Original Filed Feb. 19, 1946 2 Sheets-Sheet l wDAk COMBUSTION P 14, 1954 D. DALIN ET AL 2,689,212

PROCESS AND DEVICE FOR DESTRUCTIVE DISTILLATION Original Filed Feb. 19, 1946 2 Sheets-Sheet 2 W' .Z7av1c/ [75/217 Tare Jaizangzs Edbc'k Patented Sept. 14, 1954 UNITED STATES PAT 2,689,212 NT OFFICE PROCESS AND DEVICE FOR DESTRUCTIVE DISTILLATION Original application February 19, 1946, Serial No. 648,796. Divided and this application October 25, 1950, Serial No. 192,082. In Sweden February 10, 1945 Section 1, Public Law 690, August 8, 1946 Patent expires February 10, 1965 Claims.

This invention relates to the destructive distillation of carbonaceous material such as oil shale and is a division of the copending application, Serial No. 648,796, now abandoned, filed February 19, 1946.

Since oil shale and similar carbonaceous material upon being degassed is pyrophoric it is desirable that the same be combusted directly upon discharge from the degassing retort. This can be done in separate furnaces designed for the combustion of fuel having a low sintering temperature as, for instance, the furnace disclosed in the copending application of David Dalin et al., Serial No. 581,700, now Patent No. 2,567,058. However, it is more expedient to burn this residue coke in the same apparatus used to degas the material so that the heat of its combustion is available to heat the coking or degassing retort.

The patent to Bergh No. 1,618,566 illustrates an apparatus designed for the distillation of oil shale according to this principle. However, where the retort discharges directly into the combustion chamber as in the Bergh patent the degassing zone, i. e. the interior of the retort, is of necessity in open communication with the combustion zone. There is, therefore, the problem of preventing admixture of the distillant gases driven off from the material in the retort with the combustion gases emanating from the combustion chamber. This problem of precluding such admixture of these gases has received considerable attention in the art. One solution thereof is disclosed in the copending application of David Dalin et al., Serial No. 678,766, now Patent No. 2,550,677, wherein a predetermined pressure balance is maintained within the system to avoid the objectionable admixture of distillant and combustion gases.

Another objectionable consequence to the past methods of degassing oil shale and the like wherein the heat for the process is derived from the burning of the residue coke is the fact that the apparatus becomes objectionably high since the degassing of the material and the subsequent combustion thereof involves continued movement of the material along a single downward path. In other words, the methods of the prior art necessitated superimposing the retort above the combustion zone.

With a View toward achieving a simplified solution to the problem of possible admixture of the distillant and combustion gases and also reducing the overall height of the apparatus, the present invention has as its purpose to provide an improved apparatus for the destructive distillation of oil shale and the like wherein the degassing or coking retort is entirely isolated from, that is, has no direct communication with, the combustion chamber so that the gases cannot commingle, and wherein the combustion chamber and degassing retort are alongside each other or one within the other so that the material moving through both travels simultaneously along parallel paths rather than successively along two portions of one continuous path.

Since this invention contemplates the continuous discharge of the degassed residue coke from the bottom of the retort and the feeding thereof to the top of the furnace shaft or combustion chamber, it is essential that the material be in an easily handled condition. This means that sintering positively must be prevented, for if the material undergoing treatment in the retort is allowed to sinter it cannot be discharged and conveyed to the inlet of the furnace shaft.

An important feature of this invention, therefore, resides in the provision of means for abstracting the excess heat from the burning fuel bed and the walls of the retort to prevent raising the temperature of the material undergoing treatment in the retort to its sintering point. The means employed for this purpose comprises an arrangement of ducts distributed through the combustion chamber and along the walls of the retort through which a fluid heat absorbing medium, such as boiler fluid, either water or a steamwater emulsion, is continuously circulated.

With the above and other objects in view, which will appear as the description proceeds, this invention resides in the novel apparatus hereinafter described and more particularly defined by the appended claims, it being understood that such Changes in the precise embodiment of the hereindisclosed invention may be made as come within the scope of the claims.

The accompanying drawings illustrate one complete example of the physical embodiment of the invention constructed according to the best mode so far devised for the practical application of the principles thereof, and in which:

Figure 1 is a vertical sectional view through an apparatus embodying this invention, said view being taken through Figure 2 on the plane of the line ll and showing the retort in section and equi-spaced from two opposite side walls of the I furnace shaft which provides the combustion chamber;

Figure 2 is a vertical sectional view taken through Figure 1 on the plane of the line 22 aesam 3 and illustrating particularly the manner in which the degassed coke is discharged from the bottom of the retort and conveyed to the top of the apparatus for feeding into the furnace shaft; and

Figure 3 is a cross sectional view of Figure 1 taken on the plane of the line 33.

Referring now particularly to the accompanying drawings, the numeral 5 designates an upright furnace shaft of any suitable construction. As shown in Figure 3 this shaft, in the embodiment of the invention illustrated, is square though it will be appreciated that the specific cross sectional shape of the shaft is immaterial. Within the furnace is a degassing or coking retort 6. This retort, in the present instance is rectangular in cross section, having end walls 1 imbedded in the adjacent front and back walls 8 of the furnace shaft and side walls 9 spaced from and parallel to the opposite side walls 10 of the furnace shaft.

The retort is, of course, constructed of suitable heat conducting material and extends from a point near the bottom of the furnace shaft through the top thereof, and at its upper end has a funnel-like inlet H to facilitate charging the retort with oil shale or other material to be treated. The bottom of the retort is entirely closed off from the interior of the furnace shaft so that the degassing zone provided by the interior of the retort is isolated from the combustion zone.

The material fed into the retort through its inlet H at the top thereof passes two so-called sluice dampers 12 located on different levels to preclude leakage of gases through the top of the shaft. As the material in the retort is degassed it gradually descends, and when fully degassed is discharged from the bottom of the retort by a screw I3 or other suitable discharge device.

The screw l3 carries the degassed material through a discharge port I4 in the adjacent wall 8 of the furnace shaft and feeds it to a bucket conveyor 15 by which this material is elevated to the top of the apparatus and into two feed chutes it each leading to the top of one compartment of the furnace shaft. Shut-off dampers I! are preferably provided in the discharge ends of these feed chutes so that the top of the furnace shaft will be closed except for two flue outlets l8 which are connected by suitable ducts [9 to a chimney.

The gases distilled from the material descending through the retort are drawn off through a suction pipe shown in Figure 2 directly above the discharge screw l3.

The degassed residue coke fed into the top of the furnace shaft rests upon a grate preferably formed by a plurality of hollow rollers 2| extending across the furnace shaft and provided with means (not shown) for rotating the same. Air for combustion of the degassed material supported on the grate may be supplied in any suitable manner as by feeding it into the hollow grate rollers 2! from supply pipes 22 and manifolds 23 to be discharged through ports 24 in the rollers.

The ash resulting from the combustion drops down through the grate into an ashpit 25 which is preferably water-sealed from the atmosphere as at 26.

To preclude sintering of the material, both while it is being degassed in the retort and while it is being burned in the combustion zone, a fluid heat absorbing medium, preferably boiler fiuid, i. e. either water or steam-water emulsion, is continuously circulated through-a series of ducts 21 connected with an inlet header 28 and an outlet header 29, the headers being connected with the source of boiler fluid in any suitable manner. It is to be noted that the ducts 21 are in the nature of dependent fingers extending down into the furnace shaft from an elevation near the top thereof with some of the fingers longer than others and reaching substantially all the way down to the grate.

From Figure 3 it will also be seen that these cooling ducts are dispersed throughout the entire cross sectional area of the furnace shaft and also along the walls of the retort. The distribution of the cooling ducts is such that their cooling influence reaches all portions of the burning fuel bed and controls the transmission of heat through the walls of the retort, and the fluid cooling medium is circulated in a quantity and at a rate to abstract just enough heat to preclude having the temperature within the retort and/or within the furnace shaft reach the sintering point of the material being degassed and burned.

The present invention thus applies the teachings of the Edling Patent No. 2,504,508 issued April 18, 1950, to the distillation of carbonaceous material having a relatively low sintering temperature, and by so controlling the temperatures in the degassing and combustion zones, the success of the present method is assured since as noted hereinbefore it is important that the material after being degassed be in an easily handled condition which would not be the case if the material were allowed to sinter.

From the foregoing description taken in connection with the accompanying drawings it will be apparent to those skilled in this art that the present invention provides a simple solution to the problem of preventing the commingling of the distillant and combustion gases. in the destructive distillation of oil shale and the like by the heat derived from the burning residue coke, and that it also has the very important advantage of reducing the overall height of apparatus for this purpose.

What we claim as our invention is:

1. Apparatus for the destructive distillation of solid carbonaceous material comprising: a narrow upright retort having an inlet for raw carbonaceous material at its top and an outlet through which the gases distilled from the material leave the retort; means for feeding carbonaceous material to be degassed into the inlet of the retort to enable the maintenance of a column of material of substantial height within the retort; means for discharging degassed residue material from the bottom of the retort; an upright furnace shaft in side-by-side juxtaposition to the retort having a heat conductive wall in common with the retort so' that the combustion of fuel in the furnace shaft heats the column of material in the retort through said common wall, said furnace shaft having its interior isolated from the interior of the retort so that combustion gasses from the furnace shaft cannot commingle with distillation gases driven from the material in the retort, said furnace shaft having an inlet at its top and an outlet at its bottom; means for feeding degassed residue material from the outlet of the retort into the inlet of the furnace shaft at the top thereof to maintain a column of fuel of substantial height in the furnace shaft; means for introducing combustion air into the furnace shaft near the bottom thereof; and a plurality of ducts disposed at spaced intervals over the cross-section'of the furnace shaft and through which a fluicfheat absorbing medium flows to abstract heat from material combusting in the furnace shaft and to permit such combustion to occur without sintering through a substantial portion of the height of the column of fuel in the furnace shaft.

2. Apparatus for the destructive distillation of solid carbonaceous material wherein the heat for the process is derived from the combustion of the degassed coke, characterized by the fact that the interiors of the vessels for distillation and for combustion are isolated from one another so as not to be in direct communication with one another, to thus prevent combustion gases from commingling with distillant gases, but are in heat exchange relation with one another, having a common upright wall, so that the heat of combustion may be transferred to the carbonaceous material in the distillation vessel; further characterized by the fact that the distillation vessel is relatively narrow, so that the carbonaceous material therein may be heated substantially uniformly, all across the vessel, from said upright wall; and further characterized by the provision of a network of ducts through which a heat absorbing fluid circulates, disposed at spaced intervals through the combustion vessel to be embedded in combusting fuel therein and abstract heat therefrom so that a combustion bed of substantial depth may be maintained in the combustion vessel without danger of sintering of the combusting fuel.

3. The apparatus set forth in claim 2, further characterized by the provision of cooling ducts adjacent to said upright wall to maintain the temperature of the carbonaceous material being degassed above its sintering point and thus enable such material to be degassed in a distillation zone of substantial height.

4. Apparatus for the destructive distillation of solid carbonaceous material comprising: an upright furnace shaft having an inlet at its top and an outlet at its bottom; a narrow upright retort in side-by-side juxtaposition to the furnace shaft and having a heat conductive wall in common with the furnace shaft, the width of said retort being sufficiently small that the heating effect of said wall can reach all parts of carbonaceous material contained in the retort, said retort having its interior isolated from the interior of the furnace shaft so that distillant gases driven from the material in the retort cannot be commingled with combustion gases from the furnace shaft, said retort having an inlet for raw carbonaceous material at its top and an outlet through which the gases distilled from the material leave the retort; means for feeding carbonaceous material to be degassed into the inlet of the retort; means for discharging the degassed residue coke from the bottom of the retort; means for feeding the degassed residue coke into the inlet of the furnace shaft at the top thereof; and ducts adjacent to said common wall and disposed at closely spaced intervals, through which a fluid heat exchange medium flows to maintain temperature of the material in the retort below the sintering point thereof but near the temperature at which optimum degassing {occurs and thus enable distillation to occur through a substantial portion of the height of the column of fuel in the retort.

5. The apparatus set forth in claim 4 further characterized by the provision of ducts in the furnace shaft through which a fluid heat absorbing medium flows to abstract heat from fuel burning therein, said ducts being arranged at spaced intervals over the cross section of the furnace shaft and positioned to be embedded in fuel being combusted in the furnace shaft to hold the temperature of the fuel bed and the material being degassed below the sintering point.

6. Apparatus for the destructive distillation of solid-carbonaceous material, comprising: an upright furnace shaft; grate means in the lower portion of the furnace shaft, the space above the grate means providing a combustion zone of substantial height in which fuel is adapted to be burned to provide a source of heat; an upright retort in the furnace shaft through which solid carbonaceous material to be subsequently fed to the combustion zone is passed downwardly and in which gases are driven off from said fuel, said retort having an inlet for the raw carbonaceous material at the top of the furnace shaft and an outlet through which the gases distilled from the material'leave the retort, and said retort having upright walls spaced from the adjacent upright walls of the furnace shaft so that a substantial portion of the retort is embebbed in combusting fuel; a network of tubes confined to the furnace shaft and dispersed at closely spaced intervals transversely of the shaft throughout the combustion zone and extending through a substantial portion of the height of the combustion zone so as to be embedded in the combusting fuel, certain of said tubes being arranged in juxtaposition to said upright walls of the retort portion in the combustion zone; means for feeding water to the tubes and withdrawing steam therefrom, the cooling influence of the tubes by reason of steam generation therein precluding the attainment of temperatures in the combusting fuel and in the fuel in the retort at which sintering takes place; means for introducing raw carbonaceous fuel into the inlet of the retort; and means for withdrawing from the bottom of the retort fuel which has been degassed in its passage down the retort and transferring it to the combustion zone.

7. The apparatus of claim 6 further characterized by the fact that said tubes comprise vertically extending finger-like coils depending different distances from the top of the combustion zone, with some of the coils, including those in juxtaposition to the retort walls, extending substantially all the way to the bottom of the combustion zone.

8. Apparatus of the character described, comprising: an upright furnace shaft having a fuel inlet at its top; grate means in the lower portion of the furnace shaft; the space above the grate means providing a combustion zone of substantial height in which fuel is adapted to be burned; means for supplying air for combustion to the combustion zone; an upright retort in side-byside juxtaposition to the furnace shaft having a heat conductive wall in common with the furnace shaft so that the combustion of fuel in the furnace shaft heats and degasses raw fuel in the retort, the retort having its interior isolated from the interior of the furnace shaft and having an inlet at its top and an outlet at its bottom adjacent to the grate means; means for transferring degassed fuel from the outlet of the retort to the inlet of the furnace shaft; a network of boiler tubes confined to the furnace shaft and dispersed at closely spaced intervals transversely of the shaft and extending throughout a substantial portion of the height of the combustion zone so as to be embedded in the combusting fuel;

and means for circulating. boilen' fluid: through the tubes tothereby; simultaneous-1y." abstract: heat from. fuel; burning in the. combustion zone. for utilization elsewhere! and maintain; thetemperature within. the. furnace shaft and. the retort below the sintering point of the fuel therein;

9: IIhe. apparatus of. claim. 8, further; characterized by the. fact that certain; ofi said; boiler tubes are arranged: in.juxtaposition.torthati-portion. of: they retortv wall. which; is common; to.v the combustion zone.

10.. Apparatus. of" the character: described,.com.- prising: an uprightfurnaceshaft. having. an inletat its top grate; means. in: the furnace shaft near; the. bottom. thereof, the. space above. the gratemeans providingza combustionrzoneof sub.- stantial: height; anupright; retort. in. the furnace shaft; having. at least twoopposite walls of. heat conductive materialin common with. the furnace shaft, the distance betweenrsaidi opposite walls-of the retortbeing sufficiently. small'that. the heatingeffectof. combustion takingplacein the combustion. zone can. reach. all parts of. the retort contents. between the heated walls, said retort having; its;interior. isolated; from the interior of thefurnace. shaft ancLhaving aninletat. its top andanoutlet.through;which gases may leave the retort; means for feeding. raw fuelintothe inlet of the; retort; meansfon discharging. fuelwhich has been. heated. and: degassed from the bottom of the retort; means: for transferring suchzdischargeddegassed'fuel to the-inlet of thefurnace shaft;. a; network of: boiler'tubesconfined to the furnace. shaft. and dispersed. at closely spaced intervals transversely in. the shaft :and extending throughout aisubstantial. portion of the height of .thecombustionzone, certain'of said" tubes being in. juxtaposition to said opposite wallsof the retort; and means for circulating boiler fluid through the tubes tov thereby maintain the temperature within the furnace shaft and the retort below the sinteringpoint of the fuel therein.

References Cited in the fileof this; patent UNITED STATES PATENTS Number Name Date 1,164,295 Lutz Dec. 14', 1915 1,176,432 Chrisman Mar. 21', 1916 1,296,247 Wilkinson Mar. 4', 1919 1,418,970 P001 June 6, 1922 1,558,671 Guy-Pell' Oct. 27, 1925 1,618,566 Bergh Feb. 22,1927 1,704,956 Trumble Mar. 12,. 1929 1,712,082 Koppers May 7, 1929 1,827,483 Parr et a1 Oct. 13; 1931 1,838,622 Herrick Dec. 29, 1931 1,839,443 Shelton Jan. 5, 1932 1,858,834" Lucke May 17, 1932 1,922,321 Parker Aug; 15', 1933 1,964,639 Kropiwnicki June 26', 1934 2,165,143 Korrick July 4, 1939 2,202,245 Cramp May 28, 940 2,285,276 Hemminger June 2, 19.42 2,445,327 Keith July 20', 1948 2,504,508 Edling Apr. 18} 1950 2,550,677 Dalinet a1; May 1, 1951 2,561,334 Bowles et a1 July 24, 1951 FOREIGN PATENTS" Numb er Country Date 254,746 Germany Dec; 12, 1912 346,533 Great Britain Apr. 16, 1931 419,370 Great Britain Nov; 12, 1934 

1. APPARATUS FOR THE DESTRUCTIVE DISTILLATION OF SOLID CARBONACEOUS MATEIRAL COMPRISING: A NARROW UPRIGHT RETORT HAVING AN INLET FOR RAW CARBONACEOUS MATERIAL AT ITS TOP AND AN OUTLET THROUGH WHICH THE GASES DISTILLED FROM THE MATERIAL LEAVE THE RETORT; MEANS FOR FEEDING CARBONACEOUS MATERIAL TO BE DEGASSED INTO THE INLET OF THE RETORT TO ENABLE THE MAINTENANCE OF A COLUMN OF MATERIAL OF SUBSTANTIAL HEIGHT WITHIN THE RETORT; MEANS FOR DISCHARGING DEGASSED RESIDUE MATERIAL FROM THE BOTTOM OF THE RETORT; AN UPRIGHT FURNACE SHAFT IN SIDE-BY-SIDE JUXTAPOSITION TO THE RETORT HAVING A HEAT CONDUCTIVE WALL IN COMMON WITH THE RETORT SO THAT THE COMBUSTION OF FUEL IN THE FURNACE SHAFT HEATS THE COLUMN OF MATERIAL IN THE RETORT THROUGH SAID COMMON WALL, SAID FURNACE SHAFT HAVING ITS INTERIOR ISOLATED FROM THE INTERIOR OF THE RETORT SO THAT COMBUSTION GASSES FROM THE FURNACE SHAFT 